This invention relates generally to the provision of refrigeration to a refrigeration load, and is particularly advantageous for providing refrigeration to superconducting equipment.
Superconducting equipment operates at very low temperatures, typically below 80K. Refrigeration must be provided to the superconducting equipment on a continuing basis in order to maintain the requisite very cold conditions for sustaining the superconductivity. Often the superconducting equipment is positioned at a remote location which puts a premium on the reliability of the refrigeration system which provides the refrigeration. Most refrigeration systems require the use of at least one cryogenic pump to deliver the refrigerant fluid to the refrigeration load. The use of refrigeration systems employing cryogenic pumps may be problematic when the refrigeration system is used to provide refrigeration to superconducting equipment.
Accordingly, it is an object of this invention to provide an improved system for providing refrigeration to a refrigeration load which has high reliability and which may be effectively employed to provide refrigeration to such applications as superconductivity applications.
The above and other objects, which will become apparent to those skilled in the art upon a reading of this disclosure, are attained by the present invention which is:
A method for providing refrigeration to a refrigeration load comprising:
(A) generating a cold working gas, warming the cold working gas by indirect heat exchange with coupling fluid vapor to produce coupling fluid liquid, and forming a coupling fluid liquid reservoir having a liquid level;
(B) passing coupling fluid liquid from the coupling fluid liquid reservoir to a refrigeration load using a thermo-siphon effect, said refrigeration load being at a lower elevation than the liquid level of the coupling fluid liquid of the coupling fluid liquid reservoir; and
(C) providing refrigeration from the coupling fluid liquid to the refrigeration load and vaporizing the coupling fluid liquid to produce coupling fluid vapor for indirect heat exchange with cold working gas.
As used herein the term xe2x80x9cthermo-siphonxe2x80x9d means a process wherein a fluid is circulated in a device by providing heat which vaporizes some portion of the fluid which rises and is subsequently cooled and flows due to gravity back to the point where it can be vaporized again such that no mechanical device is used to move the fluid.
As used herein the term xe2x80x9cregeneratorxe2x80x9d means a thermal device in the form of porous distributed mass, such as spheres, stacked screens, perforated metal sheets and the like, with good thermal capacity to cool incoming warm gas and warm returning cold gas via direct heat transfer with the porous distributed mass.
As used herein the term xe2x80x9cpulse tube refrigeratorxe2x80x9d means a refrigerator device to produce low temperature refrigeration using suitable components including a pulse generator.
As used herein the term xe2x80x9corificexe2x80x9d means a gas flow restricting device placed between the warm end of the pulse tube expander and a reservoir in a pulse tube refrigerator.
As used herein the term xe2x80x9cpressure wavexe2x80x9d means energy which causes a mass of gas to go through sequentially high and low pressure levels in a cyclic manner.